This invention relates generally to the art of mounting/demounting automobile tires, and more particularly concerns devices which are useful in mounting/demounting tires on custom automobile wheels comprised of aluminum, magnesium and/or other similar metals or alloys thereof, which are easily damaged in normal tire changing operations by conventional tire changers and tire mounting/demounting devices.
Conventional automobile wheels are made from steel, which is a very hard and strong metal. Mechanical tire changers, both manual and power operated, have been developed for conventional steel wheels, and are widely used in the industry. Over the past several years, however, other metals besides steel have been used for wheels, particularly for custom automobile wheels, including aluminum, magnesium and various alloys thereof. Such custom wheels have become increasingly popular, and they are now available in a wide variety of designs. Most of the custom wheels comprise a raised central hub and four or five spokes joining the central hub to the wheel rim, although some wheels feature a central hub with a substantially solid wall joining the hub to the rim, while still others have various ribbed configurations which simulate wire wheels.
The metals used in these custom wheels, and particularly that used for the wheel hub, however, are a source of significant problems, because of their relative softness, when tires are mounted/demounted on the wheels. The rims of the custom wheels are easily scratched, marred, or otherwise damaged during mounting/demounting operations, while the wheel hub, particularly when raised, is susceptible to breakage from the action of the mounting cone, a device used by virtually all mechanical tire changers. Cosmetic damage, of course, harms the appearance of the wheel, but a broken hub requires that the wheel be replaced.
Since custom wheels are quite expensive, and since the chance of damage both to the appearance and structure of such wheels in tire-changing operations is quite high, even with considerable care on the part of the operator, most service stations, and even some tire dealers, refuse to mount/demount tires on custom wheels, or only do so on the basis of a disclaimer. Others, particularly sellers of custom wheels, have accepted the likelihood of damage and resulting loss as an inevitable cost of doing business.
Both the damage to the appearance (scratching etc.) and structure (breakage of hub) of the wheels is due, as stated above, to the relative softness of the metal used in making the custom wheels, and to the fact that the central hubs of such wheels are usually raised from that portion of the wheel connecting the hub with the rim. Conventional tire changers and the tools used therewith are made to be used with the hard steel wheels, and hence cause both appearance and structural damage to the much softer custom wheels. It is not economical, however, to design special purpose tire changers to accommodate custom wheels.
Accordingly, it is a general object of the present invention to overcome the disadvantages of the prior art noted above.
It is an object of the present invention to provide tire mounting/demounting devices which are particularly adapted for changing tires on custom automobile wheels comprising metals which are more susceptible to appearance and structural damage than conventional steel wheels.
It is another object of the present invention to provide such devices which eliminate or significantly reduce the chances of damage to the appearance of such custom wheels during tire-changing operations.
It is a further object of the present invention to provide such devices which eliminate or significantly reduce the chances of structural damage to the central hub of such custom wheels during tire-changing operations.
It is an additional object of the present invention to provide such devices which are relatively inexpensive, and which may be conveniently used by unskilled personnel.
It is a still further object of the present invention to provide such devices which are useful with existing tire changing apparatus.
It is yet another object of the present invention to provide such devices which can be used without marring or scratching the wheels.
It is an additional object of the present invention to provide such devices which may be used with wheels having different sized hubs.